Exhaust muffler



May 20, 1930.

A. BACKMAN EXHAUST MUFFLER Filed July 26. 1928 Patented May 20, 1930 PATENT OFFICE ALFRED BACKMAN, OF HALIFAX, NOVA SCOTIA, CANADA EXHAUST MUFFLER Application filed July 26, 1928. Serial No. 295,554.

My invention relates to improvements in exhaust mui'llers for internal combustion engines and the object is to provide an exhaust mufiler which will be exceptionally efiicient in eflectively mufl'ling the noise, while at the same time causing a minimum of back pressure in the exhaust line.

My invention consists in the novel construction and arrangement of parts all as hereinafter more particularly described in the accompanying specification and illustrated in the accompanying drawings, in which Figure 1 is a longitudinal, central vertical 7L5 section through my muffler, two tubes in the lower portion of the mufiier being shown in elevation.

Figure 2 is a section taken on the line 4i4 of Fig. 3.

In the drawings like characters of reference indicate corresponding parts in each figure.

In the form illustrated my invention comprises a casing having a lateral wall 5 and end walls 6 and 7 and for convenience in descrip tion the end wall 6, which is in the inlet side of the mufiier, will be referred to as the front end wall and the end wall 7 will be referred to as the rear end wall.

In the upper portion of the casing and extending inwardly thereinto through the front Wall 6 and into proximity to the rear Wall 7, is an imperforate open ended tube 8 which constitutes a gas inlet to the muffler. This tube would be held in place upon the end wall 6 in any suitable manner as by the nuts 9 and 10.

An imperforate tube 11 extends from the rear wall 7 into proximity to the front wall 6 and surrounds the tube 8, being spaced apart therefrom so as to form an annular passage 12 between the tubes. This tube 11 may be secured to the rear wall 7 in any suitable way as by rivets 13. In the lower portion of the casing and extending inwardly through the rear wall 7 into proximity to the front wall 6 is a lower imperforate open ended tube 14 which forms a gas outlet for the muffler and which tube may be held in place upon the rear wall by any suitable means, as the nuts 15 and 16.

An imperforate tube 17 extends from the front wall 6 rearwardly of the muffler and into proximity to the rear wall 7 surrounding the tube 1 1 and being spaced therefrom so as to form a passage 18 between these tubes. A water inlet 19 communicates with the casing at the top thereof and a water inlet 20 at the bottom. The casing may be reinforced by longiudinal and transverse rods 21 and 22.

The operation of my improved device is as follows: The engine exhaust is connected to the tube 8 so that the exhaust gases entering the muffler through this tube are discharged from the rear end of the tube at the rear end of the muffler, impinging against the rear wall 7. Their direction of travel is then reversed and they travel forwardly through the annular passage 12, at the front end of which they impinge against the front I end wall 6, when their direction is again reversed and they travel rearwardly and enter the rear end. of the annular passage 18 through which they travel forwardly and at the front again have their direction reversed and travel rearwardly through the tube 14 to be discharged therefrom. In their passage through the muflier they contact with the water which enters the muffler through the water connection 19 and this water not only has cooling effect upon the gases but greatly adds to the mufiling effect.

It will be noted that the outlet water connection 20 is at the bottom of the mufiier, so that immediately the engine is stopped the supply of water stopping at the same time, all water in the mufiler will immediately drain out through the outlet connection 20.

A feature of the construction is that the tubes 8, 11, 14c and 17 are all imperforate so that none of the gases may pass through the walls of these tubes but are forced to travel the full length thereof.

From the foregoing it will be apparent that I have devised an improved exhaust muffier whereby the objects of my invention have been attained.

WVhat I claim as my invention is:

A mufiier comprising a casing having side and end walls, an upper imperforate open ended tube extending longitudinally thereinto from the front end of the easing into proximity to the rear end and constituting a 5 gas inlet to the mufiier, an imperforate tube surrounding said upper tube and extending from the rear end Wall of the easing into proximity to the front end wall and forming an annular passage between said tubes, a lower imperforate open ended tube extending longitudinally into the casing from the rear end wall into proximity to the front end Wall and constituting a gas outlet from the muffler, an imperforate tube surrounding said lower tube and extending from the front end wall of the easing into proximity to the rear end wall and forming an annular passage between said last mentioned tubes, a Water inlet 'atthe-top 0f the casing, and a water outlet at the bottom thereof.

In witness whereof I have hereunto set my hand.

ALFRED BAGKMAN. 

